Relaxation Times for Chiral Transport Phenomena and Spin Polarization in Strongly Coupled Plasma

TL;DR

This paper calculates relaxation times for chiral transport phenomena in strongly coupled plasmas using AdS/CFT, clarifying their role in spin polarization and the effects of time-reversal symmetry on related fluctuations.

Contribution

It introduces a method to compute relaxation times for chiral effects in strongly coupled systems and clarifies their relation to thermal noise and symmetry constraints.

Findings

Relaxation times are derived via Kubo relations.

Time-reversal invariance enforces equalities among transport coefficients.

The study clarifies the time-dependence of the Chiral Vortical Effect.

Abstract

We compute the dynamical relaxation times for chiral transport phenomena in strongly coupled regime using the AdS/CFT correspondence. These relaxation times can be a useful proxy for the dynamical time scale for achieving equilibrium spin-polarization of quasi-particles in the presence of magnetic field and fluid vorticity. We identify the Kubo relations for these relaxation times and clarify some previous issues regarding time-dependence of the Chiral Vortical Effect. We study the consequences of imposing time-reversal invariance on parity-odd thermal noise fluctuations that are related to chiral transport coefficients by the fluctuation-dissipation relation. We find that time-reversal invariance dictates the equality between some of the chiral transport coefficients as well as their relaxation times.